This invention relates generally to trailers for hauling logs and other elongate objects.
Removing timber resources from the depths of America's forests has always presented a difficult challenge. In the past only those forest areas close to lakes and rivers could be harvested, because water was the only vehicle capable of transporting the enormous and awkward loads of timber. However, since the advent of the modern and powerful diesel equipment, logging is no longer confined to those forests areas near rivers and lakes and more remote areas have become accessible. The equipment that services these remote forest areas must be able to withstand constant punishment, because a logging road is usually so rugged and uneven that it is just barely passable. Because of the arduous nature of this transport, it is more efficient for a logging truck to haul a single large load than make two runs hauling smaller loads. These facts have long been known, and are reflected to a certain degree in the prior art.
The following patents reflect the state of the art of which applicant is aware in so far as these patents appear to be germane to the patent process:
U.S. Pat. No. 3,874,719, Goyarts PA1 U.S. Pat. No. 3,472,402, Priefert PA1 U.S. Pat. No. 4,221,525, Stedman
The patent to Stedman teaches the use of an apparatus for transporting elongated members such as logs or pipes which is suitably formed to carry logs from out of difficult terrain not having developed, adequate roadways. However, the instant invention is distinguished in that Stedman does not teach the use of a specific nesting feature for locating one trailer on top of another during transport without a payload. Furthermore, the apparatus according to the instant invention can be assembled and disassembled by a single operator employing the log loader which is integral to the apparatus.
The patent to Goyarts teaches the use of an extensible load lifting frame of the telescopic variety having a longitudinally coaxial telescopic beam structure extensible to the distance of about twice its collapsed length. The problem with this configuration is two fold. First, the inner telescoping member must be of sufficient specification to endure a heavy load, so the outer telescoping member, being larger than the inner, is of greater weight and gauge than actually required. Second, the rough and uneven logging roads cause significant torsional loading on the structural members. In the case of Goyarts this could cause significant fatigue in the structural members resulting in a inability to telescope the main beam. The instant invention is distinguished in that the two part second trailer allows significant flex because of its multi-jointed design. Furthermore, the two-part, second trailer is loaded unto the bed of the truck when not in use which saves wear and tear not only on the structural members of the second trailer but prolongs the life of the wear bearings and tires associated with the second trailer.
The remaining reference shows the state of the art further.